With the start of Amtrak operations on May 1, 1971, a single train began running between Seattle and San Diego. The unnamed train (#11/12) ran three days a week; on the other four days, another unnamed train (#98/99) ran between Oakland and Los Angeles.[5] On November 14, Amtrak extended the Oakland–Los Angeles train to San Diego, renumbered it to #12/13, and renamed it Coast Daylight. The Seattle–San Diego train became the Coast Daylight/Starlight (#11-12) northbound and Coast Starlight/Daylight (#13-14) southbound.[6] Both trains were cut back from San Diego to Los Angeles in April 1972, replaced by a third San Diegan.[7] On June 10, 1973, Amtrak began running the combined Coast Daylight/Starlight daily for the summer months.[8] Positive response led to Amtrak to retain this service, and the Coast Daylight name was dropped on May 19, 1974.[9]

An additional train, the Spirit of California, ran the section of the route between Sacramento and Los Angeles on an overnight schedule from October 25, 1981 to September 30, 1983.[10] From November 10, 1996 to October 25, 1997, through coaches were transferred between the Coast Starlight and San Diegan at Los Angeles.[11][12][13]

The Coast Starlight originally used the Southern Pacific West Valley Line between Tehama and Davis. That route included a stop at Orland, but bypassed Sacramento. On April 26, 1982, the train was rerouted via Roseville on the Southern Pacific Valley Subdivision and Martinez Subdivision, with stops added at Sacramento and Chico, per request from the state.[14][10] In 1999, the Coast Starlight was rerouted onto the more direct ex-Western Pacific Sacramento Subdivision between Marysville and Sacramento, with the Marysville stop closed.[15]

Ridership declined by 26% between 1999–2005 as freight congestion and track maintenance on the Union Pacific Railroad reduced the Coast Starlight's on-time performance to 2%, which Amtrak characterized as "dismal." By mid-summer in 2006 delays of 5–11 hours were common. Critics dubbed the train the Star-late.[16] During early summer 2008, the Coast Starlight was relaunched with new amenities and refurbished equipment. In July 2008, refurbished Pacific Parlour cars returned to service as part of the relaunch. This was much anticipated, due to the success of Amtrak's relaunches of the Empire Builder. Between FY2008 and FY2009, ridership on the Coast Starlight jumped 15% from 353,657 passengers to 406,398 passengers.[citation needed] Operating conditions on the UP improved as well; by May 2008 on-time performance had jumped to 86%.[17]

Service was suspended north of Sacramento for a month in 2017 after a freight derailment damaged a bridge near Mount Shasta, California.[18]

On February 24, 2019, train #11 struck a fallen tree near Oakridge, Oregon after a rare heavy snowstorm. The train was stranded for 36 hours before tracks could be cleared for a Union Pacific locomotive to tow the train back to Eugene-Springfield.[19]

The 2018 California State Rail Plan, prepared by Caltrans, outlines a number of planned improvements to rail infrastructure in the state of California. These proposals include near-term plans to create additional stops on the Coast Subdivision at Soledad and King City for use by the Coast Starlight.[20] There is also a proposal in the Capitol Corridor Vision plan to improve the right-of-way shared by the Capitol Corridor and Coast Starlight between Oakland and Martinez.[21] The proposal would re-route the train from along the coastline to a new tunnel through Franklin Canyon and a right-of-way next to California State Route 4 that would reduce the trip time by several minutes.

The Coast Starlight is occasionally diverted between Oakland and Los Angeles via the Tri-Valley, Central Valley, and Tehachapi Pass due to track work or service disruptions on the Coast Line. These rerouted trains are popular with railfans due to the passage through the Tehachapi Loop on the Mojave Subdivision, which has otherwise closed to passenger trains since 1971.[23][24]

The train uses double-decker Superliner I & II equipment, including a Sightseer Lounge car that has floor-to-ceiling windows to view the passing scenery. Baggage is placed in one of Amtrak's new Viewliner II single-level baggage cars or in designated coach-class cars. The Coast Starlight typically uses two GE P42DCs for locomotive power. Secondary locomotives that are occasionally utilized are the older GE P32-8BWHs and GE P40DCs. While the length of the train varies, in 2011 the "peak" consist comprised a baggage car, Transition sleeper, three sleeping cars, Pacific Parlour Car, dining car, Sightseer Lounge, and four coaches.[25]

Prior to February 2018, the Coast Starlight was unique in that it included a first-class lounge car called the "Pacific Parlour Car". The cars were Budd Hi-Level Sky Lounge cars, built in 1956 for the Santa Fe'sEl Capitan service. Called a "living room on rails", the Parlour car offered several amenities to first-class sleeping car passengers including wireless Internet access, a full bar, a small library with books and games, an afternoon wine tasting, and a movie theater on the lower level. Sleeping car passengers could also make reservations to dine in the Parlour car, which offered a unique menu not offered in the standard dining car.[26] In January 2018, in a cost-cutting measure, Amtrak announced the discontinuation of the Pacific Parlour Cars, citing the move as "part of Amtrak's ongoing work to modernize its fleet of equipment."[27] The last day of service was February 2 for northbound train 14 and February 4 for southbound train 11.